Pressure control valve and the like



Jan. 7, *1941. E. CANNON y 2,227,629.

PRESSURE CONTROL'VALVE AND THE LIKE Filed Qe. 14, 1957 Y 2 sheets-sheet1 ATTO RN EYS Jan. 7, 1941. E. CANNON PRESSURE COTROL VALVE AND THE LIKE2 sheets-sheet `2 Filed Dec. 14, 1957 INVENTOR @fn/twv,

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Patented Jan. 7, 1941 UNITED STATES PATENT QFFICE PRESSURE CONTROL VALVEAND THE LIKE Earl Cannon, Rockville Centre, N. Y., assgnor Ito E. W.Bliss Company, Brooklyn, N. Y., a corporation oi Delaware 'Ihisinvention relates to pressure control valves, and more particularly to atype of valve adapted to control the passage of nuid through a pipe linein which it is connected, and hence to 5 -control fluid pressure in saidline at the intake side of the Valve.

In various types of hydraulically-operated machinery such, for example,as hydraulic presses, it is desirable to control the passage of lo fluidthrough a conduit so that at times fluid passes therethroughsubstantially unimpeded, land at other times the passage of fluidtherethrough is restrained so that pressure may be built up in oneportion of the conduit and in any l5 passages or chambers directlyconnected thereto.

Such pressure control may, for example, be used in hydraulic presses toeither directly Vor indirectly retard the advance of the ram of thepress. Although the present invention -is particularly 20 useful in thefluid circulating systems of certain types of hydraulic presses, itwould be useful also in various other types of hydraulically-controlledor operated machines.

An important object of the present invention is the provision of animproved pressure-control valve wherein the iiuid pressure at the intakeside of the valve is employed to exert hydraulic pressure within-thevalve, tending to increase its restraint upon the passage of fluidtherethrough.

Other objects of the invention will beperceived from the followingdescription and the accompanying drawings, in which:

Figure 1 is a central vertical section of a variable pressure-controlvalve according to the present invention, the section being takensubstantially Yon the lines 2-2 of Figs. 4 and v5.

Figure 2 is a vertical section on the lines 3-3 of Figs. 1, 3 and 4.

40 Figure 3 is a horizontal section, the upper portion being taken onthe line 4-4 of Fig. 1, and the lower portion being taken on the line4a-4a of Fig. 1. f

Figure 4 is a top plan view of the variable pressure-control valveillustrated in Figs. 1, 2, and 3.

Referring to the drawings, a pressure-control valve according to thepresent invention, may comprise a suitable valve casing which houses theworking parts of the valve. Although the 50v valve is adapted to passiiuid in opposite directions therethrough, nevertheless the control isaccomplished only upon fluid passing in one direction through the valve.Therefore, reference in this speciication to an intake port or receiving55 passage or a discharge passage or port, relates only to the variablycontrollable vpassage of iluid through the valve.

In so far as the valve permits substantially uncontrolled ow of iluidthrough the valve in one direction, uid may enter the valve through a 5port |02 in the valve casing, (referring to Fig. 1) thence downwardlythrough a passage |03, thence upwardly past a check valve |04 into acentral chamber |05. The fluid may then pass from the latter chamberthrough a port |06 (in- 10 dicated in broken lines in Fig. 1), but moreclearly shown in Fig. 3, and into pipe line 64a.- The check valve |04 isonly lightly loaded bya compression coil-spring |01 seated between thesaid check valve |04 and another check valve |08 15 which is suitablyretained in place -and functions in a manner hereinafter explained.

It will be understood that the valve is adapted for connection in asingle pipe line in which, on occasions, fluid may pass in eitherdirection. As just described, the passage of fluid is substantiallyuncontrolled in the sense that the valve is not adapted to vary therestraint upon the passage of fluid therethrough. However, when iluid ispassed in the opposite directionl through the valve, that is to say,into the valve through port I 06 and out of the valve through port |02,variations in the restraint upon the passage of fluid may be effected.The following description refers particularly to passage of fluidthrough the valve in the last-mentioned direction unless otherwisespecifically indicated. Fluid, upon' entering the port |06, passes intothe central chamber |05, thence upwardly past-check valve |00 into adischarge passage |09, which connects with the port |02 through whichthe iiuid passes in leaving the valve. It will be seen that duringpassage of the fluid through the valve in the manner just described, thecheck valve |04 is held closed by the compression coil-spring |01. 40

The check valve .I 08 is loaded by a loading coilspring ||0; the upperend of which seats upon a spring cap ||0a which bears against .the innerend of a tensioning bolt.||0b threaded through a valve head the latterbeing suitably bolted or otherwise secured to the valve casing. 'Thetensioning bolt ||0b may be turned in or out to adjust the tension ofthe spring H0, and a lock nut |I0e serves to lock the said tensioningbolt after a desired adjustment of the tension of the spring ||0 hasbeen obtained. The lower end of the spring ||0 seats within ahallowed-out piston. H2 which coacts with a plunger ||3 to transmit thetension of the spring |10 to the check valve |08. The piston ||2 isaccurately fitted for hy- '55 draulic reciprocation within a bore ||4 inthe upper part of the valve casing IOI, and the plunger I I3 extendsthrough a bushing IIS which may be in the form of a stuffing box orotherwise may be adapted to prevent any substantial passage of fluidaround said plunger.

The structure of the valve, as thus far described, provides for thepassage of fluid through the valve under relatively light restraintasimposed by the check valve |08 loaded only by the spring ||0. Means areprovided, however, whereby the spring loading of the check valve |08 maybe augmented through the medium of pressure from the central chamber|05, provision being made for the imposition of such pressure upon theplunger I I3 and through the latter upon the top of the check valve |08.

The area within the bore II4 above the piston I I2 (hereinafter referredto as positive bias chamber |I6) is at all times in fluid communicationwith the area within the bore III below the said piston (hereinafterreferred to as negative bias chamber I Il) through a vertical passage|I8, and lateral passages |I0 and |20 in the valve casing. Provision ismade for selectively connecting the vertical passage |88 and theconnected of the piston bias chambers IIS and `||`l either with theexhaust passage |09 above the check valve |00 or with the centralchamber |05 below said check valve for the purpose of subjecting theplunger ||3 and the check valve |08 to either the relatively low fluidpressure present in said passage, or to the relatively high fluidpressure present in the said central chamber.

In a structure as illustrated in Fig. l, it-is` probable that fluidwould be present between the coacting surfaces of the piston I I2 andthe plunger II3, with the result that whatever fluid pressure may bepresent in the bias chambers I I6 and I I'I,

would act equally upon the equal topand bottom surfaces of the piston||2, and also, would act downwardly upon the upper end of the plunger||3 and opposethe hydraulic f orce acting upon the under side of thevalve |0d. Although the hydraulic forces acting upon the top and bottomI|2 are substantially balanced, nevertheless said piston is held incontact with the plunger I I3 by the spring I|0, and hence the forceofsaid spring is transmitted to the check valve |08. Thus the force ofthe spring ||0 and the hydraulic forces acting upon the exhaust checkvalve |08 through the plunger II3, operate as a combined force tendingto hold the check valve |08 seated against the pressure of fluid in thecentral chamber |05.

It should be apparent that the piston I|2 and the plunger ||3 may beintegral, under which arrangement the downward hydraulic forcetransmitted to the exhaust check valve |08 through the plunger I I3would be the same as if the piston and vplunger were formed separately.If said parts were integrally formed, the hydraulic force actingdownwardly upon the valve |08 would'be the hydraulic force acting uponthe top of the piston ||2, minus the hydraulic force acting upon. thebottom thereof, and as the hyl draulic force acting on the bottom of thepiston would be less to the extent of the pressure computed withreference to the cross-sectional area of the plunger H3, it follows thatthetotal hydraulic force, derived from bias chambers IIS and II'I foraugmenting the force of the spring ||0 would be the hydraulic pressurewithin said chambers computed. with reference to the cross-sectionalarea of said plunger II3, precisely the same as in the case where thepistfm and plunger are separately formed.

When the bias chambers IIS and III are connected to the exhaust passage|00 they derive little or no effective fluid pressure therefrom, and

the load tending to hold the check valve |08 closed is derived chieflyfrom the loading coilspring IIO, hence only a relatively light backpressure is present in the central chamber |05. It is understood, ofcourse, that the tension of the loading coil-spring ||0 is properlyadjusted to impose the desired relatively light restraint upon thepassage of iiuid through the valve.

When the bias chambers II6 and IIl, however, are connected to thecentral chamber |05, the relatively high pressure which is present insaid chamber, as compared to the pressure present in discharge passage|09, is transmitted to the said bias chambers and hence the plunger ||3derives a net force from such high pressure which substantially augmentsthe force ofthe loading coil-spring ||0 and thus imposes an additionalload upon the check valve |08. This additional load has the effect ofimposing an inl creased restraint upon the passage of fluid through thevalve and of accumulating an increased back pressure in the centralchamber I 05.

Means are provided for shifting the connection of the passage ||8 andthe bias chambers II@ and |II from the exhaust passage |09 to thecentral chamber |05, and 'vilce versa, for the purpose of varying therestraint to the passage of fluid through the valve and also for varyingthe back pressure in the central chamber |05 and in any conduits orchambers in other mechanisms connected thereto. To this end a pistonvalve I2I is provided, the bodyt'hereof preferably being formedintegrally withi the casing |0I. 'This piston valve comprises adouble-headed piston |22 tted accurately within a bore |23 toward thecenter of which are provided three annular chambers, one of saidchambers, numbered |20, being preferably located centrally within saidbore in fluid communication with the vertical passage IIB, as best seenin Fig. 2. Another of said annular chambers, numbered |25, is suitablyspaced from the chamber I 24 toward one side thereof and is in fluidcommunication with the exhaust passage |09 through a lateral passage|20, and the third of said annular chambers, numbered |21, is influidcommunication with the central chamber |05 through a lateralpassage |28, as best seen in Fig. 3.

The piston |22 has heads |22a and |22b at opposite ends thereof and aneck I22c intermediate said heads. When said piston is inthe extremeleft position, as shown in Fig. 2, the area around the neck |22c affordsfluid communication between the annular chambers |24 and |25, and thepiston head |22b covers the annular chamber |21?. 30

In the position just referred to' only the relatively low pressure inthe exhaust passage |09 is communicated to the bias chambers I I0 and II1, and little or no additional load 1s imposed thereby upon the valve|08. When the piston |22 is moved to an extreme right position, the areaaround the neck |2Zc affords fluid communication between the annularchambers |24 and I2I, and the piston head I22a covers the annularchamber I2|. In thisposition the relatively high pressure in the centralchamber |05 is communicated to the bias chambers IIS and III, andsuillcient additional bias may thereby be imposed upon the check valve|08 to increase the restraint upon fluid passing through the valve andto increase the pressure in the central chamber and in any conduits orchambers of connected mechanisms.

A coil-spring |29 coacts with one end of the piston |22 and with a cap|30 closing one end of the bore |23, whereby to urge the said pistontoward its extreme left position, as shown in Fig. 2, while said pistonis moved to its extreme right position by an electric solenoid 6B in amanner well under-l stood in the art. A plunger I3! of the said solenoidmay be pivotally connected by a link |32 to one end of a bell-cranklever |33, fulcrumed at |36 upon a bracket |35 which may be suitablymounted upon the casing |0|. The other end of the bell-crank |33 may bepivotally connected through a link H30 to the outer end of extension|l3l of the piston |22, said extension passing through a cap |38 and asuitable stulng boxl |39. Thus, when the solenoid 56 is electricallyenergized, the piston |22 moves to its extreme right ever, 'not beingshown as such showing is not necessary to an understanding of theinvention. Likewise, it will be understood that a suitable electricswitch or circuit breaker may be employed in the electric circuitsupplying such energy, and that in any machinery in which the presentvalve is employed, such a switch may be operated either manually orautomatically, at any desired stage in a cycle of operation whereby tooperate the valve either to impose a relatively light restraint upon thepassage. of fluid therethrough, and consequently to establish only arelativelylight back pressure at the intake side of the valve or tooffer substantial restraint to the passage to fluid therethrough andhence to establish a substantial back pressure at the intake side of thevalve.

Although, as hereinbefore stated, the present invention may be employedin various types of hydraulic machinery, a fuller understanding of theinvention may be obtained by considering its operation in connectionwith a hydraulic press. The present invention may be advantageouslyemployed in a hydraulic press structure as disclosed in United States lLetters Patent No. 2,152,837, issued under date of April 4, 1939. Thesaid patent discloses a. hydraulic press having a preflll valve which isnormally open during the greater part of the advance stroke of the presswhereby to permit 'fluid to be drawn rapidlyinto the ram chamber of thepress in substantial volume. The ram of the press illustrated in saidpatent is caused to advance rapidly during a substantially initialportion of its advance stroke by -means of iiuid injected under pressurethrough a centrally located supply tube into a relatively smallhydraulic chamber located within the ram itself. During thisrapidadvance portion of the stroke, fluid is being discharged from return orpush-back chambers, and the prell valve meanwhile remains open. One ofthe characteristics of the prell valve disclosed in said patent is thatwhen the ram of the press is substantially impeded during its advancestroke, the pressure of the fluid being pumped into the press increasessubstantially and automatically causes the preytially increasing theback pressure in the ram rell valve to close, after which iluid underpressure may continue to pass into the press, but instead of going onlyinto the small hydraulic chamber employed in the rapid initial advanceof the ram, it passes into the mainram chamber and hence the continuedadvance of the ram proceeds at much reduced speed and greater hydraulic`force may be applied to the ram because of the larger areas of the twochambers within which the high pressure fluid continues to operate. l

It will be obvious that in such a press the prefill valve may be causedto close, and hence the speed of the advance of the ram may be mate--rially reduced, either by the resistance which the ram and the diecarri-ed thereby may encounter upon the die engaging the material beingWorked, or by the expedient of establishing pressure in the ram returnchamber shortly before engagement of the die with the material. Where itis desired to avoid impact of the die with the material being worked,the latter expedient naturally would be preferred.

In order to avoid such impact in the operation of such a hydraulic pressstructure, avalve according to the present invention may be connected inthe conduit employed to effect discharge of the ram return or push-backchamber, with the intake side of the valve nearest to the said chamber.With the valve so connected, the solenoid 66 and its controllingelectric connections may be so arranged that Aduring the rapid advanceportion of the stroke of the press the said solenoid is not energizedand hence the piston |22 would be disposed as shown in Fig. 2, in whichposition the bias chambers ||6 and ||1 are connected through the lateralpassage |26 to the exhaust passage |09 in which the fluid, being on thedischarge sideof the check valve |08, is at relatively low pressure;hence, during the rapid advance portion of the stroke of the ram theiuid being exhausted from the ram return chamber would suffer onlyslight impediment to its passage through the valve.

Let us assume, however, that an electric sv'itch or circuit breaker,disposed in the electric circuit controlling the solenoid 66, is soarranged on or adjacent to the slide of the press that it is engaged andclosed by a suitable abutment carried by said slide just before the dieengages the material being worked. Immediately upon the closing of suchswitch or circuit breakerthe solenoid iil` becomes energized andimmediately shifts the piston |22 toward the right as viewed in Fig. 2,thus connecting the bias chambers ||6 and of the valve with the centralchamber |05 through lateral passage |28 (see also Figs. 1 and 3).

Thereupon the bias chambers ||6 and ||1 immeturn or push-back chamber ofthe press. As a result of this increased back pressure the preiill valveof the press immediately closes, whereupon the advance of the ramcontinues at a much reduced speed and increased hydraulic force may beapplied to theram of the press to complete the work of the advancestroke.

The invention is not intended to be limited to the specific form whichhas been described and disclosed herein and in the accompanying draw- 75ings for the purposes of illustration, but should `be regarded asincluding modiilcations and variations thereof within the'sccpe of theappended claim.

y I claim:

A variable pressure control valve or the like comprising ya receivingpassage, a discharge passage, a port between said passages permittingmovement of fluid from the former to the latter passage, a check valveadapted to close said port, a spring arranged to impose a load upon saidcheck valve urging the latter closed against pressure in said receivingpassage, hydraulic means, augmenting said spring, and also adapted toimpose a load upon said check valve, and a controlling mechanism,adapted to connect or disconneet the said hydraulic means relatively tothe said receiving passage, whereby respectively to render said checkvalve substantially responsive 2,2Z7,6:`wl

e either to both the said spring and hydraulic means or to the saidspring alone, the said hydraulic means comprising a hydraulicallyactuated piston adapted to transmit force to said check valve, ahydraulic positive bias chamber, adapted to co-act with the piston toimpose an inwardly-acting load thereupon, a. hydraulic negative biaschamber, adapted to cof-act with the piston to impose anoutwardly-acting load thereupon, partly oisetting the saidinwardlyacting load, and connecting passages affording hydrauliccommunication between both said bias chambers and the receiving passage,the said controlling mechanism controlling the communication of pressurethrough said connecting passages to establish a common pressure in bothsaid bias chambers and in the receiving passage.

EARL CANNON.

